I plan on making a 27 slot mailbox for my wife (who is a 1st grade teacher). She made it clear that she wanted clear plastic shelves in it verse using wood or anything like that. Seems everywhere I’ve looked, still 9×12ish sheets of plastic are crazy expensive. Am I looking at the wrong thing? Doesn’t seem like a thin piece of 9×12 plastic should cost 3-4 bucks each. While she would prefer clear, solid color plastics would work too. While talking to my dad, he suggested that I get some cheap clipboards and remove clip part.

“plastic” is like “wood.” except that it’s a lot harder to tell one petroleum product from the other. I am not an expert, but I keep the stuff around and, (confession) buy clipboards at thrift stores and save the plastic.

Acrylic is generally the cheapest. It tends to be brittle and you need a sharp, many-toothed blade on your table saw.

Polycarbonate is the one that will bend and bend and not shatter (think motorcycle windshields). There’s more, but I list these just because they’re the most common.

Rick and Ron: right on. At least get some quotes for the stuff and present it to the professor. Perhaps an alternative would be hardboard (Masonite) painted with high quality oil base product in primary colors.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

Cut edges on plastic are very sharp, be sure to ease the exposed edges.

That can be done in many different ways:

torch the edges, easiest but the trickiest … to much heat = warped plexiglass

round over or chamfer bit and polish

sanding, least visually appealing unless it is followed by a polish

Other point:

You can torch polish Polycarbonate and Plexiglass.

Polycarbonate can only be made clear after sanding/machining by vapor polishing.

ABS, the plastic used in DWV (Drain Waste Vent) may be cheaper but it is not as strong in the same thickness is not available in clear. It is the easiest to machine and can be polished with fine grit paper.

If she doesn’t mind solid colored plastics, you could try Ikea. Yes, Ikea. They do have planks made of wood with laminated plastics that can be use for shelve. If you asked me, lamination would be the cheapest option you have. Of course if you’re willing to spend, good quality plastic boards are easily available in plastic distributors or fabricators. You can even get them to cut to size and smoothen for you. You might have to think about a sort of carrier for transport as they can break quite easily on impact. Make sure they are wrapped properly and if they are really long, you might need your wife to help carry so each of you can be at both ends. Leave whatever you bought in its wrapper/carrier until the moment of installation to prevent scratches.